/* MD5
 converted to C++ class by Frank Thilo (thilo@unix-ag.org)
 for bzflag (http://www.bzflag.org)
 
   based on:
 
   md5.h and md5.c
   reference implementation of RFC 1321
 
   Copyright (C) 1991-2, RSA Data Security, Inc. Created 1991. All
rights reserved.
 
License to copy and use this software is granted provided that it
is identified as the "RSA Data Security, Inc. MD5 Message-Digest
Algorithm" in all material mentioning or referencing this software
or this function.
 
License is also granted to make and use derivative works provided
that such works are identified as "derived from the RSA Data
Security, Inc. MD5 Message-Digest Algorithm" in all material
mentioning or referencing the derived work.
 
RSA Data Security, Inc. makes no representations concerning either
the merchantability of this software or the suitability of this
software for any particular purpose. It is provided "as is"
without express or implied warranty of any kind.
 
These notices must be retained in any copies of any part of this
documentation and/or software.
 
*/
 
#ifndef COMMON_SOURCE_MD5_H
#define COMMON_SOURCE_MD5_H
 
#include <cstring>
#include <iostream>
#include <cstdio>
namespace md5 {
	// Constants for MD5Transform routine.
#define S11 7
#define S12 12
#define S13 17
#define S14 22
#define S21 5
#define S22 9
#define S23 14
#define S24 20
#define S31 4
#define S32 11
#define S33 16
#define S34 23
#define S41 6
#define S42 10
#define S43 15
#define S44 21
// a small class for calculating MD5 hashes of strings or byte arrays
// it is not meant to be fast or secure
//
// usage: 1) feed it blocks of uchars with update()
//      2) finalize()
//      3) get hexdigest() string
//      or
//      MD5(std::string).hexdigest()
//
// assumes that char is 8 bit and int is 32 bit
class MD5
{
public:
  typedef unsigned int size_type; // must be 32bit
 
								  // default ctor, just initailize
  MD5()
  {
	  init();
  }
  // nifty shortcut ctor, compute MD5 for string and finalize it right away
  MD5(const std::string& input) :MD5(input.c_str(), (size_type)input.size())
  {
  }
  // MD5 block update operation. Continues an MD5 message-digest
  // operation, processing another message block
  void update(const unsigned char *input, size_type length)
  {
	  // compute number of bytes mod 64
	  size_type index = count[0] / 8 % blocksize;

	  // Update number of bits
	  if ((count[0] += (length << 3)) < (length << 3))
		  count[1]++;
	  count[1] += (length >> 29);

	  // number of bytes we need to fill in buffer
	  size_type firstpart = 64 - index;

	  size_type i;

	  // transform as many times as possible.
	  if (length >= firstpart)
	  {
		  // fill buffer first, transform
		  memcpy(&buffer[index], input, firstpart);
		  transform(buffer);

		  // transform chunks of blocksize (64 bytes)
		  for (i = firstpart; i + blocksize <= length; i += blocksize)
			  transform(&input[i]);

		  index = 0;
	  }
	  else
		  i = 0;

	  // buffer remaining input
	  memcpy(&buffer[index], &input[i], length - i);
  }
  // for convenience provide a verson with signed char
  void update(const char *input, size_type length)
  {
	  update((const unsigned char*)input, length);
  }
  // MD5 finalization. Ends an MD5 message-digest operation, writing the
  // the message digestRaw and zeroizing the context.
  MD5& finalize()
  {
	  static unsigned char padding[64] = {
		  0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
		  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
		  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
	  };

	  if (!finalized) {
		  // Save number of bits
		  unsigned char bits[8];
		  encode(bits, count, 8);

		  // pad out to 56 mod 64.
		  size_type index = count[0] / 8 % 64;
		  size_type padLen = (index < 56) ? (56 - index) : (120 - index);
		  update(padding, padLen);

		  // Append length (before padding)
		  update(bits, 8);

		  // Store state in digestRaw
		  encode(digestRaw, state, 16);

		  // Zeroize sensitive information.
		  memset(buffer, 0, sizeof buffer);
		  memset(count, 0, sizeof count);

		  finalized = true;
	  }

	  return *this;
  }
  // return hex representation of digestRaw as string
  std::string hexdigest() const
  {
	  if (!finalized)
		  return "";

	  char buf[33];
	  for (int i = 0; i<16; i++)
		  sprintf(buf + i * 2, "%02x", digestRaw[i]);
	  buf[32] = 0;

	  return std::string(buf);
  }
  friend std::string digestString(const void * input, unsigned int length);
  friend std::string digest(const void * input, unsigned int length);
private:
	MD5(const void *input, size_type length)
	{
		init();
		update((const char*)input, length);
		finalize();
	}

	void init()
	{
		finalized = false;

		count[0] = 0;
		count[1] = 0;

		// load magic initialization constants.
		state[0] = 0x67452301;
		state[1] = 0xefcdab89;
		state[2] = 0x98badcfe;
		state[3] = 0x10325476;
	}
  typedef unsigned char uint1; //  8bit
  typedef unsigned int uint4;  // 32bit
  enum {blocksize = 64}; // VC6 won't eat a const static int here
 
						 // apply MD5 algo on a block
  void transform(const uint1 block[blocksize])
  {
	  uint4 a = state[0], b = state[1], c = state[2], d = state[3], x[16];
	  decode(x, block, blocksize);

	  /* Round 1 */
	  FF(a, b, c, d, x[0], S11, 0xd76aa478); /* 1 */
	  FF(d, a, b, c, x[1], S12, 0xe8c7b756); /* 2 */
	  FF(c, d, a, b, x[2], S13, 0x242070db); /* 3 */
	  FF(b, c, d, a, x[3], S14, 0xc1bdceee); /* 4 */
	  FF(a, b, c, d, x[4], S11, 0xf57c0faf); /* 5 */
	  FF(d, a, b, c, x[5], S12, 0x4787c62a); /* 6 */
	  FF(c, d, a, b, x[6], S13, 0xa8304613); /* 7 */
	  FF(b, c, d, a, x[7], S14, 0xfd469501); /* 8 */
	  FF(a, b, c, d, x[8], S11, 0x698098d8); /* 9 */
	  FF(d, a, b, c, x[9], S12, 0x8b44f7af); /* 10 */
	  FF(c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */
	  FF(b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */
	  FF(a, b, c, d, x[12], S11, 0x6b901122); /* 13 */
	  FF(d, a, b, c, x[13], S12, 0xfd987193); /* 14 */
	  FF(c, d, a, b, x[14], S13, 0xa679438e); /* 15 */
	  FF(b, c, d, a, x[15], S14, 0x49b40821); /* 16 */

											  /* Round 2 */
	  GG(a, b, c, d, x[1], S21, 0xf61e2562); /* 17 */
	  GG(d, a, b, c, x[6], S22, 0xc040b340); /* 18 */
	  GG(c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */
	  GG(b, c, d, a, x[0], S24, 0xe9b6c7aa); /* 20 */
	  GG(a, b, c, d, x[5], S21, 0xd62f105d); /* 21 */
	  GG(d, a, b, c, x[10], S22, 0x2441453); /* 22 */
	  GG(c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */
	  GG(b, c, d, a, x[4], S24, 0xe7d3fbc8); /* 24 */
	  GG(a, b, c, d, x[9], S21, 0x21e1cde6); /* 25 */
	  GG(d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */
	  GG(c, d, a, b, x[3], S23, 0xf4d50d87); /* 27 */
	  GG(b, c, d, a, x[8], S24, 0x455a14ed); /* 28 */
	  GG(a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */
	  GG(d, a, b, c, x[2], S22, 0xfcefa3f8); /* 30 */
	  GG(c, d, a, b, x[7], S23, 0x676f02d9); /* 31 */
	  GG(b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */

											  /* Round 3 */
	  HH(a, b, c, d, x[5], S31, 0xfffa3942); /* 33 */
	  HH(d, a, b, c, x[8], S32, 0x8771f681); /* 34 */
	  HH(c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */
	  HH(b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */
	  HH(a, b, c, d, x[1], S31, 0xa4beea44); /* 37 */
	  HH(d, a, b, c, x[4], S32, 0x4bdecfa9); /* 38 */
	  HH(c, d, a, b, x[7], S33, 0xf6bb4b60); /* 39 */
	  HH(b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */
	  HH(a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */
	  HH(d, a, b, c, x[0], S32, 0xeaa127fa); /* 42 */
	  HH(c, d, a, b, x[3], S33, 0xd4ef3085); /* 43 */
	  HH(b, c, d, a, x[6], S34, 0x4881d05); /* 44 */
	  HH(a, b, c, d, x[9], S31, 0xd9d4d039); /* 45 */
	  HH(d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */
	  HH(c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */
	  HH(b, c, d, a, x[2], S34, 0xc4ac5665); /* 48 */

											 /* Round 4 */
	  II(a, b, c, d, x[0], S41, 0xf4292244); /* 49 */
	  II(d, a, b, c, x[7], S42, 0x432aff97); /* 50 */
	  II(c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */
	  II(b, c, d, a, x[5], S44, 0xfc93a039); /* 52 */
	  II(a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */
	  II(d, a, b, c, x[3], S42, 0x8f0ccc92); /* 54 */
	  II(c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */
	  II(b, c, d, a, x[1], S44, 0x85845dd1); /* 56 */
	  II(a, b, c, d, x[8], S41, 0x6fa87e4f); /* 57 */
	  II(d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */
	  II(c, d, a, b, x[6], S43, 0xa3014314); /* 59 */
	  II(b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */
	  II(a, b, c, d, x[4], S41, 0xf7537e82); /* 61 */
	  II(d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */
	  II(c, d, a, b, x[2], S43, 0x2ad7d2bb); /* 63 */
	  II(b, c, d, a, x[9], S44, 0xeb86d391); /* 64 */

	  state[0] += a;
	  state[1] += b;
	  state[2] += c;
	  state[3] += d;

	  // Zeroize sensitive information.
	  memset(x, 0, sizeof x);
  }
  // decodes input (unsigned char) into output (uint4). Assumes len is a multiple of 4.
  static void decode(uint4 output[], const uint1 input[], size_type len)
  {
	  for (unsigned int i = 0, j = 0; j < len; i++, j += 4)
		  output[i] = ((uint4)input[j]) | (((uint4)input[j + 1]) << 8) |
		  (((uint4)input[j + 2]) << 16) | (((uint4)input[j + 3]) << 24);
  }
  // encodes input (uint4) into output (unsigned char). Assumes len is
  // a multiple of 4.
  static void encode(uint1 output[], const uint4 input[], size_type len)
  {
	  for (size_type i = 0, j = 0; j < len; i++, j += 4) {
		  output[j] = input[i] & 0xff;
		  output[j + 1] = (input[i] >> 8) & 0xff;
		  output[j + 2] = (input[i] >> 16) & 0xff;
		  output[j + 3] = (input[i] >> 24) & 0xff;
	  }
  }
 
  bool finalized;
  uint1 buffer[blocksize]; // bytes that didn't fit in last 64 byte chunk
  uint4 count[2];   // 64bit counter for number of bits (lo, hi)
  uint4 state[4];   // digestRaw so far
  uint1 digestRaw[16]; // the result
 
  // low level logic operations
  // F, G, H and I are basic MD5 functions.
  static inline uint4 F(uint4 x, uint4 y, uint4 z) {
	  return (x & y) | ((~x) & z);
  }
  static inline uint4 G(uint4 x, uint4 y, uint4 z) {
	  return (x & z) | (y & (~z));
  }
  static inline uint4 H(uint4 x, uint4 y, uint4 z) {
	  return x^y^z;
  }
  static inline uint4 I(uint4 x, uint4 y, uint4 z) {
	  return y ^ (x | (~z));
  }
  // rotate_left rotates x left n bits.
  static inline uint4 rotate_left(uint4 x, int n) {
	  return (x << n) | (x >> (32 - n));
  }
  // FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
  // Rotation is separate from addition to prevent recomputation.
  static inline void FF(uint4 &a, uint4 b, uint4 c, uint4 d, uint4 x, uint4 s, uint4 ac) {
	  a = rotate_left(a + F(b, c, d) + x + ac, s) + b;
  }
  static inline void GG(uint4 &a, uint4 b, uint4 c, uint4 d, uint4 x, uint4 s, uint4 ac) {
	  a = rotate_left(a + G(b, c, d) + x + ac, s) + b;
  }
  static inline void HH(uint4 &a, uint4 b, uint4 c, uint4 d, uint4 x, uint4 s, uint4 ac) {
	  a = rotate_left(a + H(b, c, d) + x + ac, s) + b;
  }
  static inline void II(uint4 &a, uint4 b, uint4 c, uint4 d, uint4 x, uint4 s, uint4 ac) {
	  a = rotate_left(a + I(b, c, d) + x + ac, s) + b;
  }
};
/**
 * 生成指定数据的MD5,为null时返回空对象
 */
inline std::string digest(const void * input, unsigned int length)
{
	if (nullptr != input) {
		MD5 md5 = MD5(input, (MD5::size_type)length);
		return std::string((char*)md5.digestRaw, sizeof(md5.digestRaw));
	}
	return std::string();
}
inline std::string digest(const std::string& input)
{
	return digest(input.data(), (unsigned int)input.size());
}
/**
 * 生成指定数据的MD5并转为HEX字符串返回,为null时返回空对象
 */
inline std::string digestString(const void *input, unsigned int length)
{
	if (nullptr != input) {
		MD5 md5 = MD5(input, (MD5::size_type)length);

		return md5.hexdigest();
	}
	return std::string();
}
inline std::string digestString(const std::string& input)
{
	return digestString(input.data(), (unsigned int)input.size());
}

#undef S11 
#undef S12 
#undef S13 
#undef S14 
#undef S21 
#undef S22 
#undef S23 
#undef S24 
#undef S31 
#undef S32 
#undef S33 
#undef S34 
#undef S41 
#undef S42 
#undef S43 
#undef S44 

} /* namespace md5 */ 
#endif /* COMMON_SOURCE_MD5_H */